The invention relates to 2-,5-,6-,7-,8-substituted oct-2-en-4-ones, to a process of using these compounds as a fragrance, an aroma, or a flavoring, and to fragrance or aroma compositions prepared therewith.
Until the discovery of the 1-(2,2,6-trimethylcyclohexyl)but-2-en-1-ones, called damascones, a perfumistic reconstitution of rose oil was virtually impossible (D. Kastner, Parfuem. Kosmet. 1985, 66, 5-16; D. Kastner, Parfuem. Kosmet. 1994, 75, 170-181). With the discovery of the damascones (G. Ohloff, E. Demole, J. Chromatogr. 1987, 406, 181-183), however, not only did this change, but the substance class also gave many other floral or fruity accords volume, freshness and naturalness. Moreover, excessive amounts set entirely new trends (M. Gras, Perfum. Flavor. 1990, 15, 25-28; M. Gras, Perfum. Flavor. 1992, 17, 1-12). There have been many attempts to find substances with similar odor properties, some of which have become established in perfumery (G. Frxc3xa1ter, J. A. Bajgrowicz, P. Kraft, Tetrahedron 1998, 54, 7633-7703). However, these compounds are structurally very similar to the damascones and, apart from a few exceptions, are constitutionally isomeric thereto. In addition, the Japanese laid-open specification JP 55027135 discloses 3(4),4(5)-diseco- and 2(3),4(5)-diseco-damascones. From a perfumery viewpoint, all of these compounds offer very little which is new, i.e. they broaden the odor spectrum around the parent compounds only insignificantly, and thus do not satisfy the need for novel innovative scent building-blocks of this odor direction.
As a result of the structural similarities and the similar molecular weight, the known compounds having damascone-like odor properties established in perfumery have very similar application properties, i.e. a comparable diffusivity, substantivity, and radiative power in compositions. They do not, in fact, satisfy the need for innovative, novel scent building-blocks with other areas of application.
An object of the invention is to rectify this deficit and to extend the odiferous spectrum of the damascones by novel facets in order to open up new composition possibilities for the perfumer and flavorist.
Accordingly, it would be advantageous to provide a group of branched acyclic alkenones of the general formula I: 
in which
R1 and R2 are independently CH2, CH3, CHCH3, or CH2CH3;
R3 is H, CH3, or CH2CH3; and
R4, R5, R6, R7 are independently H or CH3,
with the proviso that the radicals R4, R5, R6, and R7 are not all hydrogen at the same time, and where the dashed line represents an optional double bond. This new group of compounds enriches the typical odor properties of the damascones with novel, characteristic aspects. Such compounds have completely different application properties, primarily with regard to a much greater diffusivity and radiative power. Some of these compounds are also much more odor-intensive than the damascones themselves.
Another embodiment of the present invention is a process for preparing a fragrance, a flavor, or an aroma composition wherein a base material is combined with a compound of the general formula I: 
wherein
R1 and R2 independently are CH2, CH3, CHCH3, or CH2CH3;
R3 is H, CH3, or CH2CH3;
R4, R5, R6, and R7 independently are H or CH3; with the proviso that R4, R5, R6, and R7 are not all hydrogen, and where the dashed line represents an optional double bond.
A further embodiment of the present invention is a process for delivering a fragrance, flavor, or aroma to a substrate by contacting a substrate with a fragrance, flavor, or aroma composition comprising a base material and a compound of formula I: 
wherein
R1 and R2 independently are CH2, CH3, CHCH3, or CH2CH3;
R3 is H, CH3, or CH2CH3;
R4, R5, R6, and R7 independently are H or CH3; with the proviso that R4, R5, R6, and R7 are not all hydrogen, and where the dashed line represents an optional double bond.
The present invention provides 2-,5-,6-,7-,8-substituted oct-2-en-4-ones according to formula I: 
wherein
R1 and R2 independently are CH2, CH3, CHCH3, or CH2CH3;
R3 is H, CH3, or CH2CH3;
R4, R5, R6, and R7 independently are H or CH3; with the proviso that R4, R5, R6, and R7 are not all hydrogen, and where the dashed line represents an optional double bond.
According to the general formula I, a double bond does not have to be present at positions R1(C-5), C-5(C-6), and R2(C-6). (E/Z)-Isomers of all double bonds (at most two) present in a molecule and all possible stereoisomers are covered by the general formula I, which is shown in the formula by waved lines.
The compounds according to the invention are therefore characterized by an oct-2-en-4-one skeleton. Due to the specific odor and/or aroma properties, compounds with a 7-methyloct-2-en-4-one skeleton are preferred, and compounds with a (5Z)-7-methylocta-2,5-dien-4-one skeleton are particularly preferred.
The general formula I thus covers the compounds 1-9: 
The compounds of the general formula I are particularly suitable for the composition of rosy accords, and generally floral bouquets. Particular mention is to be made also of the use in fruity notes and musk-accentuated compositions. However, the use is neither limited to these accords, nor to specific fragrances, classes of substance, or odor notes. Examples of further classes of substances which harmonize well with the compounds of the present invention and that may be combined therewith include:
The compounds of the present invention may be combined, alone or in combination, with a base material to form a fragrance, a flavor, or an aroma composition. As used herein, a xe2x80x9cfragrance, a flavor, or an aroma compositionxe2x80x9d includes perfumes, detergents, soaps, creams, shampoos, hair conditioners, food stuffs (including gum), beverages, and food. As used herein, a xe2x80x9cbase materialxe2x80x9d includes any standard formulation conventionally found in a fragrance, a flavor, or an aroma composition as defined above. Examples of typical base materials are set forth in Examples 10 and 11.
The present invention also includes a process for providing a fragrance or aroma. This process includes combining one or more compounds according to formula I with a base material to form the fragrance or aroma composition. The fragrance or aroma composition is then applied to a substrate or liberated, in the case of a candle by burning. As used herein, a xe2x80x9csubstratexe2x80x9d means a surface to which a fragrance or aroma composition is typically applied. Thus, for example, a substrate may be human skin in the case of a perfume, soap, or cream; hair in the case of a shampoo, mousse, or gel; a fabric in the case of a detergent or fabric softener; or a hard surface in the case of a cleaning agent.
The following examples are provided to further illustrate the compounds, compositions, and processes of the present invention. These examples are illustrative only and are not intended to limit the scope of the invention in any way.